A perfunctory gesture? Hardly. It defines you. It defines the exchange. A hands-on study of a subtle craft.

THE HAND IS AN INTIMATE BODY PART. Its very shape and condition tell a lot about who you are. I've always hated my hands. They're meaty and fat, the very definition of a paw. In college I worked several jobs--cleaning dumpsters, pitchforking rocks out of a freshly tilled soccer field, carrying ten-gallon buckets of hot pitch across the roof of a large shopping mall--that built up a very nice, very manly set of calluses. My father used to check them by shaking my hand from time to time. He liked it when they were nasty rough, though his were always ultrasmooth. To him, this seemed to define the gap between us. I was a kid who worked his vacations because he needed the money; he was a boss who skipped his by choice.

Shaking hands, it follows, is an intimate act, though this might not be agreed upon outside the discussion board for obsessive hand-washers. But if a kiss is intimate, why not a handshake? The other night I was watching some half-assed TV show in which a guy kissed a girl, then looked at her and said, "You're a good kisser." I groaned. My teenage son was there, cutting a peach into little pieces, not paying much attention. "A kiss is not that easy," he said. He doesn't talk much, but I could tell he was speaking from experience--recent experience. "It's not like a handshake or anything."

So true, my little man, so true. A kiss is not like a handshake. It's far easier than a handshake. A kiss you perform mostly in private, again and again. Why wouldn't you get better?

But a good handshake--now that is a subtle business.

TRUTH BE TOLD, a man who has a good handshake can do any goddamned thing he wants. I'm not saying he will; I'm saying he can. He can work a room--one person to the next, shaking with strangers, with old colleagues, with huge men and tiny women alike--with his hand. People remember him; they listen to him. Men like this are followed.

The good handshake demands a particularly strong command of several divergent elements of influence in a single gesture, in one smallish moment, in order to connect with a person whom (presumably) you have never met before. Think of the components: a swift, elegant movement toward the waiting hand, wise use of the eyes, the considered grip strength, even the rhythm of the shake is important. All that and you have to speak, too; you have to be engaged enough to muster a question, remember a name, acknowledge some common experience while you grip, shake, and release.

Isn't a handshake just another grim layer of social obligation? Isn't there a reason it's called glad-handing? Well, for a person who's interested in influence, social obligation is more of a tool than a barrier, one that demands use and examination. And it's only glad-handing if the shake is cheap, insincere. So I went forth, spending the better part of two months searching out the perfect handshake while crafting a better one for myself.

In that period, I shook hands with a candidate for county commissioner, two priests, three general contractors, an ice-cream salesman, a U. S. senator, a typewriter repairman, a dry cleaner, three women playing shorthanded bridge at a sandwich shop, seven of my son's friends, my ex-wife, her new husband, a woman selling jelly at a New York State Thruway stop, six bellmen, one hotel desk clerk, a concierge, four maitre d's, a guy who runs a moving company, a sawmill operator, two cops, one professional card dealer, a mathematician, a biologist, a "sandwich artist," the captain of the Maid of the Mist IV, two parking valets, one waiter, two waitresses, a yogi, and three NBA players. In the process I had my arm rotated like a piston on a steam engine and my shoulder jerked practically out of its socket. I received seven shake-appendant gangster hugs. My hand was brushed, crushed, scratched, and double squeezed.

I found that if I held on just two beats longer than usual, people stopped what they were saying and eyeballed me. They saw me. This worked particularly well with people who were working for me--the desk clerks, the bellmen, the valets, the concierge. I knocked down at least one suite upgrade with that alone. I also discovered that if I gradually increased the pressure of a shake, people would automatically smile. Really. It was like I was blowing up some balloon in their face. Unless you went at it too hard. And once I had them smiling, then, well, I had them.

And the people I saw every day? The ones I work with or buy my coffee from? With them I learned to be quick and efficient. They liked a shake, sure, but they didn't want to mess around with it. In and out. Keep a rhythm. Let them know you're there for them.

The people I met only once, like the senator? Or the yogi? I wanted them to remember me. I gave them the business. I reached out slowly, without looking down, gripped, and gave my own little doorknob twist at the wrist, playful but not bouncy, holding it until the very end of what I had to say, until the very last syllable dropped away. It cracked the senator up. The yogi did a double take.

ONE THING TO KNOW about the range of handshakes: It's a menagerie, a bunch of animals, each replete with its own characteristics, tendencies, and warning signs. Figure out what sort of animal you are dealing with, deconstruct the handshake, and you can tell a lot about what's about to happen.

A long, deep shake by a hand that is a bit too large for you, a bit too clammy, one that lingers, with an undifferentiated grip strength, fingers on your wrist just a little too long? That's your son's Pop Warner coach. Well, he shakes like an alligator. Filthy animal. Alligators lie under the water, like dead logs, till they flip their jaws up and crush an egret in one flashing movement. A guy like that is just acting like he's calm, because he knows people expect that he's too big and too strong for his own good. He is. I'm not talking about the fish grip, the one that a really big guy gives you because he's just a little jumpy about people being afraid of him. Those guys let go as soon as you do. Different animal. I'm talking about alligators. I once interviewed Kyle Turley, then the left tackle for the Saints, famous for throwing his helmet across the field in anger. He slipped me a big-time gator--slow and scaly--and I just knew he was pretending to be small for me.

There are people who shake like a sparrow, making their hand smaller than it needs to be, lighting upon the other person's hand rather than gripping it. This is a lousy shake. It conveys the commitment of a bird that lives its entire life caught in the posture of scanning the physical world for predators. If you are going to lift your hand from your side in the first place, then get in there. Apply pressure. Dwell in it a bit.

And then there are the Big Cats. Cool name, but these guys aren't animals at all. They're salesmen, and their handshakes tell you so. They show strength--extra-firm grip, an insistent rhythm, a bizarre enthusiasm--but it is more of a reminder of what they want from you than it is a statement of self. These are the kinds of guys who learned their handshake in a seminar somewhere. They might use two hands--one for the shake, the other to grasp the bend of your elbow unnecessarily. Note to Big Cats: An accent like this should be reserved for moments that matter--funerals, state dinners, the closing of estates.

My best handshake is a sidewinder--coming in with my wrist cocked a bit, swinging my hand on a little orbit from the hip. I use it when I'm happy to see people. I found that once I paid attention to it, I was pulling the other person closer, just a bit, by turning his hand toward me with just the subtlest pinch of domination.

A handshake sets the tone. I like to dominate a little, to define things a bit at the start, so I do my little doorknob twist, or I pull the person in for a little hug. That is my way; it doesn't have to be yours. Just don't look at the other person's hand while you're reaching; that's a tell, a sure sign of insecurity. Look at his face, his eyes; concentrate on what he is showing you.

THE ONE HANDSHAKE I most remember was my father's when I went to visit him in a nursing-care center in Albany, where he is recovering from a stroke. He was in his wheelchair when I got there, facing the window. I reached over his shoulder to touch his hands, and he pulled me around for a look and a shake.

"Pop," I said, reaching out and taking his hand. It was smooth as ever, though a little loose. I gave him the extra pressure, a bit of a sidewinder pull, and bent down for a kiss. "Wow, nice grip," he said. "Your hands are soft. You must be making real money." I told him I was doing okay. I asked how he was, and he allowed that he'd been better. He told me he loved the trees where he lived now. Didn't I like the trees? I turned for a look, but it was hard to see, because he held my grip. I have learned that sometimes you don't let go.